The last day of Christmas is called the Feast of the Epiphany. It is a religious holiday observed by Christians to commemorate the visit of the Magi to the Christ child. In the Greek Orthodox religion it is called Theophany, which means, "the shinning forth and manifestation of God."
The Feast of the Epiphany is also known by the names Feast of the Manifestation, the Adoration of the Magi, the Festival of the Three Kings and Three Kings Day. It is celebrated on January 6 and marks the end of the 12 days of religious observance that begin on Christmas Day.